Telephony.



E. R. CORWIN.

TELEPHONY.

APPLICATION FILED JAN. 15. I915. 1,173,??6. Patented Feb. 29,1916.

2 SHEETS-SHEET I.

WITNE $132.2? KNVENTOR /m/ ELMER KCORWIN ATTURNEY E. R. CORWIN.

TELEPHONY.

APPLICATION FILED JAN-15.1915.

1, 173,776. Patented Feb. 29, 1916.

2 SHEETSSHEET 2.

INVENTOR ELMEKRCQRWIN 5 short circuited,

outrun s'rn'rns rnrnn r onrron.

ELMER .R. CORWIN, OF CHICAGO, ILLINOIS, ASSIGNOR TO FRANK B. COOK COMPANY,

OF CHICAGO, ILLINOIS, CORPORATION OF ILLINOIS.

TELEPHONY.

Specification of Letters Patent.

Patented Feb. 29-, rare.

Application filed January 15, 1915. Serial No. 2,390.

To all 'whom it may concern Be it known that I, ELMER R. CoRWIN, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Telephony, of which the following is'a full, clear, concise, and exthoseregular call receiving operators that are normally available for extending calling lines and may normally be reached for-this purpose by calling subscribers are replaced by special operators when lines are placed out of working condition as, for example, by accidental. grounds and short circuits. This feature, of the invention is of service not only to guard against the extension of accidentally grounded telephone lines to reg ular operators but also is of service in guard ing-against the application of regular calling lineextensions to incoming ends of accidentally grounded telephone lines extending from subscribers stations or other stations.

As I have practised the invention the regular operators are automatically replaced when telephone-lines are grounded and are replaced by the operation of the regular operators themselves when telephone lines are In accordancewith the preferred embodiment of the 'inventlonthe means which the regular operators employ for substituting special operators are used by the regular operators also to substitute special operators for which the regular operators have insufficient or unadaptableequipment. For example, one party line subscriber may wish to converse with another subscriber upon the same line, in which case it is desirable to have the called party line subscriber signaled by equipment presided over-by a special operator whereby the efficiency of the regular cperatcrin her regular routine of extending callinc telephone lines will not be impaired. Where trouble men or others may wish to know the line designations of .certain subscribers telephone lines which they are using: or in the case of fire or other emergency calls, or in the case of parties who the equipment of the system.

have made improper'use of telephone lines it is desirable to have the information concerning the designations of such lines brought within the knowledge of a special operator who may call back over these lines, extend the same where necessary, and mention or report the designations thereof.

My invention also has for its object the provision of indicating means'to denote the number of occasions and preferably the extent of such occasions when the link connectorsasslgned to each operator or otherwise employed are all taken for use whereby the operating manager may be guided in grouping the telephone lines to suit the capacity of the operators or the capacity of The various features of my invention are of particular service in that class of telephone exchange systems wherein the regular receiving operators do not preside over signal devices that are individual to subscribers lines, though the invention is not to be restricted in its adaptation to such telephone systems. In practising that feature of my invention whereby a regular receiving operator may substitute equipment of a special operator in connection with a calling line, I desirably use a part of such calling line, or extension thereof, or the answering end of the employed regular operators link connector connected with such calling line and which itself also constitutes a calling line extension, the connecting end of the link connector or other line extension being in each case excluded from the connection or connecting means whereby the special operator is reached. In the preferred embodiment of the invention the connectingmeans by which the special operator is reached inoludes a portion of the calling line, the adjacent endof the link connector and also another calling 'line extension. I will explain the foregoing and other features of my' invention more fully by referwhich includes indicating mechanism for determining the frequency with which the operators link connectors are fully taken for complete use of the link'connectors at the telephone receiver and telephone transmit-r diflerent positions.

I have shown two subscribers telephone stations 200, 201 ateach 'of which there is located equipment that includes a telephone switch hook 1, a telephone receiver 2, a telephone transmitter 3, a call bell 4, and a condenser 5, the switch hook being provided with a normal contact that includes the bell and condenser in bridge of the associate line when the receiver is upon the hook and an alternate contact whereby the ter are included in theline when the switch hook .is free of the receiver. The limbs of each telephone line extend to the exchange, the normal circuit relation and the normal environment thereof being such that when the receiver at a-calling station is removed from its switch-hook a circuit is established which is traceable from the grounded common battery 6 (the illustration'of this battery being repeated throughout the diagram for the sake of clearness, though it is tobe understood that one battery 'is preferably employed), the upper armature switch of the cutoff relay 7 and its contact, both sides of the calling line, by way of the calling station, the lower armature switch of the cutoff relay and its contact, to the grounded winding of the line relay 8. The line relay is thereupon energized to establish -a cir- 'cuit traceable from the grounded battery 6 through the winding of the individual switch starting relay 9 (that pertains to a master switch common to a number of link connectors), the upper armature switch-of the master switch driving relay 10'and its contact, the lower armature switch of said line relay, to its then engaged and grounded contact. The starting relay 9, being energized, attracts its armature switch to es-' tablish a circuit traceable from the groundarmature switch of relay 9 to its then engaged and grounded contact. It is understood that the similarly positioned waiting contacts of the individual electro-magnetic switches belonging to the magnets 11 of a roupare in multiple connection.. If the W1 ers 15, 16, 17 and 18 of the employed individ ing contacts pertaining to the calling line ual electro-magnetic switch do not happen to be resting in contact with waitthe magnet 11 is set into operation until these wipers engage such contacts whereby the motor magnet 11 is deenergized to permit these wipers to remain in association with the calling line, this result being due to the operation of thearmature switch or relay 14 which in turn is due to the then established circuit through the relay 14 traceable from the grounded battery 6, the winding of this relay, the wiper-l9 of the master switch, the waiting contact engaged by this wiper and individual to the individual motor switch, the wiper 18 of this switch, the waiting contact engaged by this wiper and individual to the calling line,

the upper armature switch of the line relay 8, to its then engaged and grounded contact. Obviously if the wiper 18 happens to be in engagement with a waiting contact that belongs to the calling line the relay.

14 will be instantly energized so, that the -'motor magnet 11 will not operate, The

opening of the circuit of the motor magnet 11 at the armature switch of the relay 14 is followed by the closure of another circuit The armature switches of relay 20 are now attracted, the two topmost armature switches of this relay engaging their contacts to complete the contacting strands of the employed link connector or line joining calling line extension whose answering end terminates in the wipers 15, 16 and whose connecting end is shown in the form of a connecting plug 27' but to which form of connecting end forthe link connector or line extension the invention is not to be limited The armature switch of the relay 20 which is illustrated immediately above the core of this relay is now included in. a circuit traceable. from the, grounded common battery 6 through the winding of the cutolf relay 7, the wiper 17 of the employed individuaL electro-mag'netic switch and the waiting'fcontact engaging the same and which pertains to the calling line, the armature switch of the special operators calling relay 23 that is illustrated immediately above the core of this relay, the normal contact of this armature switch, to.

the aforesaid and grounded armature switch of the relay 20 and its then engaged contact. The cutoff relay 7 is thus energized to attract its armature switches and open circult for the associate line relay 8 whereupon the armature switches of this line of an idle link connector an relay are separated from their grounded contacts to open circuit for the'relays 9 and 14 whereby these relays restoretheir armature switches to normal. i

When the relay 20 was energized acircuit was established at its lowermost armature switch traceable from the grounded battery 6, the master switch driving relay 10, the wiper 2i of the associate master switch and the waiting contact engaging the same, the said lowermost switch of the calling transmitter battery relayl20 and its engaged alternate contact, to the grounded lowermost armature switch of the special operator calling relay 23 and its normal contact;- When the relay 10 is energized it opens the circuit of the individual switch starting relay 9 which is common to alLof the motor magnets 11 of a group whereby no other calling line may have access to any motor magnet 11 of the group to which the relay 9 iscommon until the relay 10. is againdeenergized. After the employed motor magnet 11 has become associated with'the calling line the master switch having the wipers13, etc.,

and which is common toja group of motor magnets 11, is operated to predetermine the next motor magnet 11 which is'to be operated to connect another calling line with another one of the group of link'connectors having the group of magnets ll To this end the motor magnet 25 pertaining to the master switch is now included in a circuit which is traceable from the common grounded battery 6, the winding of the motor magnet 25, the lower armature switch ofthe now energized relaylO, the right hand pair of contacts of the button 26 individual .to some idle link connector or a number of such pairs of contacts in multiple, the

middle armature switch of the called transmitter battery relay 27 of an idle link connector and the contact engaging this switch, the lowermost armature switch of the relay the normal contact of this switch, to the 'ottom and rounded armature switch of the relay 23 of suchidle link connectorby way of-the normal contact of this armature switch. The magnet 25 will continue in operation "until the wiper 24 engages a waiting contactpertainingto some unemployed link connector from which ground is removed by the operation of a relay or relays of such unemployedvlink connector. The motor magnet 25 as now brought to rest with its associatewipers of" the master switch in association with some 11 which will be the next idle motor-magnet to be employed when a new call is initiated by a calling subscriber. -When all of the motor magnets 11 of a group have been'taken for use to extend calling linesthe motor magnet 25 of the master switchcommon to the magnets' ll of their group will notoperate owing to the energized condition of relays belongingi'tothe link connectors having such motorm'a'gnets 11. The wipers of the master switchffwill then remain in association with waiting contacts individual to the last link connector taken for use, at which time the relay 10 is energized to close the adjacent gap in the-circuit of the motor magnet 25 to place the motor magnet in conditionfor immediate operation when any of the link connectors have been restored to normal,

whereupon the wipers of the master switch will seek the firstidle link connector if they do not already rest upon waiting contacts 3 individual thereto. The buttons 26 are only to be manipulated when the link connectors to which they are individual are to be thrown out of service or made artificially busy wherebyeach operator may have apportionedv to her the number of link connectors which she is adapted efficiently to handle. When abutton' 26 is depressed for this purpose'the contacts of the right hand pairare separated and the contacts of the left hand pair are connected, the first, ef-. fect being to. prevent the closure of circuit for the motor magnet 25 by way of apparatus pertaining to the abandoned link connector and the second effect being to place ground upon the waiting contact individual to the abandoned link andengaged by the wiper 24 of the master switch to prevent 'tors telephone outfit 28, details of which obviously do not .have to be described, is common to the link connectors or line extensions of a group adapted for interchangeable connection with calling and called lines and may have association with any link connector which is taken for use by'means-of the listening key 29 individual to such link connector. The operator knows which listening key to depress by the presentation to view of a signal 30 that is oper'ated by the relay 20. After such listening key has been depressed the operator is in telephonic connection with the calling subscriber and will, after the usual test, engage the connecting end or plug 27 of the employed link connector with the ]ack or other sw tch .31 pertaining to the wanted line, assuming that the service desired by the calling subscriber is of an ordinary nature. Transmitter battery is furnished to the called party by way of the windings of the associate called transmitter battery relay 27 between whose windingsthe common battery 6 is included and together with Which windings t is in bridge of the strands of the employed link connector. The link isnot within her capacity to perform, such regular operator will depress the button 33 individual to the link connector that now joins the calling subscriber with this regular operator to close a gap in the circuit which includes an interrupter 34, the grounded common battery 6, theresistance 35, say of five hundred ohms, and the winding of the associate special operator calling relay 23, which is sluggish in release. When the relay 23 has been energized it presents a' signal 36 to view, whereupon the operator may release'the depressed button 33, the circuit of the relay 23- being maintained, due to the sluggishly releasing action thereof,

bymeans of a circuit traceable from the grounded battery 6, the cutoff relay 7, the wiper 17 and its engaged waiting'contact, the armature switch and relay 23' that is shown immediately above its core, the alternate contact of this armature switch, the winding of this relay to the grounded interrupterBla As the cutoff relay 7 is quick to respond while the relay 23 is slow to re lease, the armature switches of relay 7 will vibrate while the armature switches of the relay 23 will remain attracted during the circuit openings effected by the interrupter 34 whereby the commongrounded battery 6, in addition tobeing'included in the. circuit just traced, is also intermittently included in circuit with .a line lamp 37 appearing before the special operator and individual to the calling line, each line having an individual signal or line lamp before its operator. The stated arrangement of the lamps or other operators responsive devices 37 is preferred but I do not wish to be limited to the use of responsive devices 37 that are individual to the subscribers lines nor to the nature of such responsive devices The circuit just intermittently established for this lamp is traceable from the common battery 6, the

, lamp individual to the callingline that desires special service, the upper armature switch of the cutoff relay 7 individual to this calling line, the contact engaged bythis armature switch, the talking wiper 15; the topmost armature switch of the energized relay 23.; to the grounded-and alternate contact of this switch. The energized relay 23 in addition to operating the signal'37 individual to the calling subscriber that desiresflashing lamp 37' that is individual to the calling subscriber desiring special service will extend her telephone outfit 38 into connection with such calling line by means of some suitable switching appliance such as an answering plug 39 inserted within a 1 multiple jack, 40 pertaining to the calling subscriber and by the depression of a listening key 41 if such be employed. When the plug39 is first inserted, within such jack 40 a shunt is established about the relay 23 of the employed regular 'operators link connector which is traceable from the grounded calling supervisory relay 42, say of twenty ohms resistance, the heel of the answering plug 39, the thimble of the jack 40,, the'cutofirelay 7, of say five hundred ohms, to the grounded battery 6, the associated relay 23 being thereupon denergized as it is of, say one thousand ohms resistance. The armature switches of the relay 23 are nowrestored to normal and the associate link connector is placed in condition Where it may again become appropriated by the master switch for connection with a. calling line.

The special operator, being nowin communication with the calling subscriber who desires special service, will respond to the in-' quiries of the calling subscriber and there after.withdraw ..the answering plug 39 if this is all of the service which the calling subscriber wishes. If, however, the calling subscriber should desire connection with another subscriber upon thesame line with him, assuming that the calling line is a party line, the special operator will with- 'draw the answering plug 39 from the calling subscribers jack 40 after having requested the calling subscriber to hang up his receiver, whereafter she will insert the connecting plug 43 in the, jack 40 of theparty the-calling generator 44 in circuit with such line with the aid of the ringing key 45. If,- however, the calling subscriber, having had certain peculiar inquiries answered. should wish connection with another subscriber upon a dliferent line, the answering plug 39 w1ll remain in its orlgmal connection and the plug 4C3 will be inserted within the jack line and ring the calling and called parties upon the party line by properly including phone .bridgefat lithe corresponding sub-.

willnot be necessary, fit being sufficient to add that thereis illustrated, a called supervisoryrelay. -16, I p I v I One o f the} cases oftrouble, and which is to be correctedwith theaid of a special op erator, is that whiohfarises when a. shunt (such as isi indicatedby the dotted line 47) is accidntally; placed across thesides of a telephonedine; the shunt being followed by the connection of a regular opertor with such line" in the manner. which has hithert o been describedssincef the accidental shunt performs a calling fline extending. function that isiperformed'fby the subscribers telephonefbridgefwhen;it"is completed across a calling; line. fWhen the selected regular op. eratoranswers-the supposedly incoming call and gas; no sponse she substitutes the equipment of the spteia o rato for her own equipment i "he manner "which has been specified." Whetefaf ground, such as is indicated'by h d l I as. accid n ally; Occu up n one side pf"? a subscribefisi line,'.' the signal lamp 537 individual tosuch L n andappean ing before} the [speeial l operator is caused t ad y.. b" l ili h sj p be ng uded in a. circuit traceable from grounded y: 6AM; lamp? 7; t e ap i m t e switch of tlie cutoff ,elay 7, an t0 he gr u i i l-g lith s d iided 0 1 tionindicatedati49 placed uponthe other side f,".-a subscrib line said 15 1937 .vvill be caused steadily} o qlow 'receivel, 2 at the-correspondingQsubstatio v removed from; its. .hook,.. rcuit beingfe'stablished traceable'from th .groundedfbattery 6, the

lamp 37, th upper .a in tu ewitch f toff relay 7 and its engaged conta n: the tele:

scribers station totli'e ground 49. The special operator will first attend; to: those lines whose lamps are; being intermittently flashed from the regularfoperatorsposition,

I knowingthat. suchlines areflin needof more immed ate attent on. than the hnes upon which grounds have occurred as indicated by the steadily glowing lamps. As the: in-

,vention is preferably practised the signal lamps 37 do notrglow unless the lines to which they are individual are accidentally grounded or unlessthey are caused to glow by a regular operator. When a calling subscribers line is grounded upon either side the associate line relay 8 is shunted so that its "contact;

lines to regular operators but also is of servlce 1n guard ng against the appl cation of regular calling line extenslons to accidentallygrounded lines and this feature of the U Referring now more particularly to Fig.

3,",though Fig. 1 may also be referred to, I haveillustrated two groups of link connectors each having connecting plugs 27'; at different operators positions. The. magnets 27 belonging to each group of linkconnectors have their bottom armature switches included in; serial relation in a circuit which includes anindicator operating magnet a, each group of link connectors having a magnot at individual thereto. The indicating instrument of Which the magnet at forms a part mayinclude a suitable record;- 'receiv'- ing element such as therecording drum indicated at 72 revolved at. a uniform rate of speed to enable the magnet ato apply the recording pen o thereto when all ofthe mag:

not employed but remains active tomake arecord whenever all of themagnets'27of thegroup to which it'belongs are energized. If-an indicator 1) should s'how that'the vlink connectors in a groupj'to -which such'findL' cator is individual are too frequently completely employed or are (completely employed for periods oftime that are too long, the numberof telephone lines assign'edfto the operator having such links may be .reduced by having some of them transferred to anotheroperator whose indicatoi b would show that such transfer could be permitted. The usual transfer board d may, of course, be employed in effecting the desiredredistribution. a n a. U

While I have herein shown and particularly. described the preferred embodiment of my invention I do not wish to be limited to the exact details of construction and circuit arrangement shown as changes may readily be made Without departing fromthe spirit of my invention, but

Having thus described my invention 1 claim as new and desire to secure by Letters Patent the following 1. -A telephone exchange system including telephone lines extending to an exchange; line extensions for interchangeable connection with the'incoming endsof such lines in the normal operation of, the exchange; other telephone line extensions that are to be excluded from connection between.

1 of the system; and responsive devices associated with these latter extensions and having means whereby they are unresponsive to telephone lines in normal condition and are responsive to telephone lines inabnormal condition.

3. A telephone exchange systemincluding telephone lines extending to an exchange; line-extensions for interchangeable connection with the incoming ends of such lines in the normal operation of the exchange; other telephone line extensions that are to be excluded from connection between'calling and called lines in the normal operation of the system; and operators responsive devices, individual to the telephone lines, associated with these latter extensions and having means whereby they are unresponsive to telephone lines in normal condition and are responsive to telephone lines in abnormal condition.

4. A telephone exchange system including telephone lines extending to an exchange; line extensions for interchangeable connection with the incoming ends of such lines in the normal operation of the exchange; other telephone line extensions that are to 7 be excluded-from connection between calling and called lines in the normal operation of the system; and responsive devices, individual to the telephone lines, associated with these latter extensions and having means whereby they. ,are unresponsive to telephone lines in normal condition and are responsive to telephone lines in abnormal condition.

5. A telephone exchange system including telephone lines extending to an exchange;

line extensions for interchangeable connection with the incoming ends of such lines in the normal operation of the exchange; other telephone line extensions that are to be excluded from connection between calling and called lines in the normal operation of the system; and operators responsive devices associated with these latter extensions and having means whereby thev are responsive to telephone lines in normal ccnditivn and are responsive to accidentally grounded telephone lines.

- 6. A telephone exchange system including telephone lines extending to an exchange; line extensions for lnterchangeable connection with the incoming ends of such lines in the normal operation of the exchange;

other'telephone lineextensions that are to be excluded from connection between calling and called lines in the normal operation of the system; and responsive devices associated with these latter extensions and hav-- ing means whereby they are unresponsive to telephone lines in normal condition and are responsive to accidentally grounded telephone lines.

' 7. A telephone exchange system'including telephone lines extending to an exchange; line extensions for interchangeable connection 'with the incoming ends of such lines in the normal operation of the exchange; other telephone line extensions that are to be excluded from connection between calling and called lines in the normal operation of the system; and operators responsive devices,'individualto the telephone lines, as-

sociated with these latter extensions and having means whereby they are unresponsive to telephone lines in normal condition and are "responsiver'to accidentally grounded telephone lines.

8. A telephone exchange system including telephone lines extending toan exchange; line extensions ,for interchangeable connection with the incoming ends of such lines in-the normal operation of the exchange: other telephone line extensions that are to be excluded from connection between calling and called lines-in the normal-operation of the system; and responsive dev ces, individual to the telephone lines, associated with these latter extensions and having means whereby they are unresponsive to telephone lines in normal condition and are responsive to accidentally grounded telephone lines.

9. A telephone exchange system including telephone lines extending to an exchange;

line extensions for uniting lines in conversation and in interchangeable association with the incoming ends of telephone lines to effect the extension of these lines to a regular operaters position; other line extensions pertaining to a special operators position for uniting lines in c nversation and in inciation with the incoming ends of telephone lines to effect the extension of these lines to a regular operators position; other line extensions pertaining to a special operators position for uniting lines inconversat on and in interchangeable association withthe incoming ends of telephone lines toeflect the extension of these lines; a special operators responsive device; 7 and means controlled by the regular operator for operating said responsive device independently o'f'the connecting ends of the line extensions under her control and by 'way of the answering ends of these line extensions and the incoming ends of the telephone lines. v

11. .A telephone exchange system including telephone lines extending exchange; line extensionsfor,unitinglines in conversation; electro ina-gnetic switches for eflecting the interchangeable association of the line extensions the incoming Lends or telephone lines to eaectthe extension 'of these lines to a regular'operators position;

other line extensions pertaining to'a, special operators 'position for 'nni'ting' lines conversation and in I interchangeable association with the incoming ends oiiitelephone lines to effect the extension 'ofjtheselines; a operators responsive dew and" trolled the regularofierathrifono erating connecting ends of linel 'lextensi'ons' under her control an'd by wa of the answering these lines to a regularfoperator s' position; other-line extensions pertaining to] a special operators positionfor uniting lines" conversation and inii'nterehangeable association with the incoming endsof telephone lines to eifect the extension of thes'e lines; a spe'cial operators responsive device and meanscontrolled by the regular operator for operating said responsive device independently of'the connecting ends of the line extensions under her control and by way of the answering ends of these line extensions and the incoming ends of the telephone lines. 13. A telephone exchange system including telephone lines extending to an exchange; line extensions for uniting lines in conversation; electro-rnagnetic switches for efiecting the interchangeable association of the line extensions with theincoming ends of telephone ;lines to effect the extension of these lines to a regular operators position; other line extensions pertaining to a special operators position for uniting lines in conversation and in interchangeable association said responsive device 'iiidependeiit 'yflof 'ithe,

these lines with the incoming ends of telephone lines to effect the extension of these lines; a special operators responsive device; and means controlled by the regular operator for operating said responsive device independently of the connecting ends of the line extensions under her control and by way of employed electro-magnetic switches.

14. A telephone exchange system including"telephone lines extending to' an exchange line extensions for uniting lines in conversation; 'electro-Inagnetic switches for eflecting the interchangeable association of the line extensions with the incoming ends of; telephone lines to effect the extension of these lines to a regular operators position; other line extensions pertaining to a special operators" position for uniting lines in conversation and in interchangeable association with the incoming ends of telephone lines to effect the extension of these lines; a special operators responsive device; and means/controlled by the regula'r operator for operatmg said responsive device. independently of the connectingf end s of the line extensions ufid fh igntral by way of the answering i'ias'x' nphone exchange system includir'ig'"telephone" lines extending to an" exchange extensions for uniting lines in conversation electro-ma'gn'etic switches for eii'ect'ing the interchangeable association 'of the line" e"xtensio'ns' with the incomingends of; telephone Qli sfto efifect" the extension bf W n v to'a gularo rate rs position; otherfline extens a' j'pertamiii toa special qpeyapors position for" uniting lines in conversation intenchangeahle association withf'theiinconiing ends of telephone lines to effect the'extensionfof these lines a special operators responsive device; and means controlled bythe regular operator for-operating said responsive device independently of the connecting ends of thelineextensions under her control by way of the answering endsof these line extensions and the incoming ends of the telephone lines and by way of employed electro magnetic switches;

16. A telephone exchange system including telephone lines extending to an ex change; line extensions for uniting lines in conversation; electro-magnetic switches for efi'ecting the interchangeable association of the line extensions with the incoming ends of telephone lines to efl'ect the extension of these lines to a regular operators position; otherline extensions pertaining to a special 7 operators position for uniting lines in conversation and in interchangeable association with the incoming ends of telephone lines to effect the extension of these lines; a special operators responsive device: and means controlled by the regular operator for operating said responsive device independently of the connecting ends of the line extensions under her controlby way of the incoming ends of e the telephone lines and by way of employed sion of these lines; a special operators responsive device indiyidual to telephone lines; and means controlled by the regular operator for operating said responsive device independently of the connecting ends of the line extensions under her control and by way of the answering ends of these line extensions. Y

18. A telephone exchange system including telephone lines extending to an ex-' change; line extensions for uniting lines in conversation and in interchangeable association with the incoming ends of telephone lines to efi'ect the extension of these lines'to a regular operators position; other line extensions pertaining to a special operators T position for uniting lines in conversation and in interchangeable association with the incoming ends of telephone lines to efi'ect the extension of these lines; a special operators responsive device individual :to telephone lines; and means controlled by the regular operator for operating said responsive device independently of the connecting ends of the line extensions under her control andjby way of the answering ends of theseline extensions and the incoming ends of the telephone lines.

19. A telephone exchange system including telephone lines extending to an exchange;'line extensions for uniting lines in conversation; electro-magnetic switches vfor effecting. the interchangeable association of the line extensions with the incoming ends of telephone lines to efi'ect the extension of these lines to a regular operators position; other line extensions pertaining to a special operators position for unitinglmes 1n con versation and in interchangeable association with the incoming ends of telephone lines to effect the extension of these lines; a special operators responsive device individual to telephone lines; and means controlled by theregular operator for operatin said respon sive device independently of the connecting ends of the line extensions under her control and by wav of the answering ends of these line extensions. 20. A telephone exchange system includmg telephone lines extending to an exchange; line extensions for uniting lines in conversation; electro-inagnetic switches for effecting the interchangeable association of the line extensions with the incoming ends of telephone lines to effect the extension of these lines to a regular operators position; other line extensions pertaining to a special operators position for uniting lines in conversation and in interchangeable association with the incoming ends of telephone lines to effect the extension of these lines: a special operators responsive device individual to telephone lines; and means controlled by the regular operator for operating said responsive device independentlyof the connecting ends of the line extensions under her control and by way of the answering ends of these line extensions and the incoming ends of the telephone lines.

21. A telephone exchange system includ ing telephone lines extending to an exchange; line extensions for uniting lines in conversation; electr c-magnetic switches for effecting the interchangeable association of the line extension with the incoming ends of telephone lines. to effect the extension of these lines to aregular operators position; other line'extensions pertaining to" a special operators position for uniting linesin conversation and in interchangeable association with the incoming ends of'telephone lines to effect the extension of these lines a specialoperators responsive device individual to the telephone lines; and means controlled by the regular operator for operating said. re-

sponsive device independently of the connecting ends of the line extensions'under her magnetic switches. I

- 22; Atelephone exchange system includcontrol and bv way of employed electroing telephone lines extending to an ex change; line extensionsrfor' umtin lines in conversation; electro-magnetic switches for effecting the interchangeable association of the lineextensionswith the incoming ends of telephone lines to effect the extension of these lines to a regular'operators position; other line extensions pertaining to a special operators position for unitinglines in conversation and in interchangeable association with the-incoming ends of telephone I lines to effect the extension of these lines: a speclal operators responsive device individual to the telephone lines; and means controlled by the regular operator for operating said responsive device independently of the connecting ends of the line extensions under her control by way of he answering ends of these line extensions and by way of employed electro-magnetic switches.

23. A telephone exchange system including telephone lines extending to an exchange; line extensions for uniting lines in conversation; electro-magnetic switches for efiecting the interchangeable association of 130 the line extensions with the incoming ends versation and in interchangeable association with the incoming ends of telephone lines to effect the extension of these lines; a special operators responsive device individual to the telephone lines; and means controlled by the regular operator for operating said responsive device independently of the connecting ends of the line extensions under her control by way of the answering ends of these line extensions and the incoming ends of the telephone lines and by way of employed electro-magnetic switches.

24. A telephone exchange system including telephone lines extending to an exchange; line extensions for unitlng llnes in conversation; electromagnetic switches for elfecting the interchangeable association of the line extensions with the incoming ends of telephone lines to effect the extension of these lines to a regular operators position; other line extensions pertaining to a special operators position for uniting lines in conversation and in interchangeable association with the incoming ends of telephone lines to effect the extension of these lines; a special operators responsive device individual to the telephone lines; and means controlled by the regular operator for operating sald responsive device independently of the connecting ends of the line extensions under her control by way of the incoming ends of the telephone lines and by way of employed electro-magnetic switches.

25. A telephone exchange system including telephone lines extending to an exchange; a group of link connectors at the exchange for uniting lines in conversation; a master switch common to said link connectors and having related thereto means whereby it will become link connector to predetermine it for use and will leave association with this link connector when this link connector is taken for use to become associated with a new unemployed link connector; electromagnetic switches individual to the link connectors and adapted by the master switch for operation to connect the answering ends thereof with the incoming ends of the telephone lines; and means for preventing the operation of the electromagnetic switches through the master switch when all of said link connectors have been taken for use.

26. A telephone exchange system including telephone lines extending to an exchange; a group of link connectors at the exchange for uniting lines in conversation: a

master switch common to said link connectors and having related thereto :neans whereby it will become associated with an associated with an idle idle link connector to predetermine it for use and will leave association with this link connector when this link connector is taken for use to become associated with a new unemployed link connector; electro-magnetic switches individual to the link connectors and adapted by the master switch for operation to connect the answering ends thereof with the incoming ends of the telephone lines; and means for preventing the operation of the master switch when all of the link connectors have been taken for use.

27. A telephone exchange system including telephone lines extending 'to an exchange; a group of link connectors at the exchange for uniting lines in conversation; a master switch common to said link connectors and having related thereto means whereby it will become associated with an idle link connector to predetermine it for use and will leave association with this link connector when this link connector is taken for use to become associated with a new unemployed link connector; and operator controlled means for preventing the operation of the master switch when all of said link connectors have been taken for use.

28. A telephone exchange system including telephone lines extending to an exchange; line extensions for uniting lines in conversation and in interchangeable association with the incoming ends of telephone lines to effect the extension of these lines to a regular operators position; other line extensions pertaining to a special operators position for uniting lines in conversation and in interchangeable association with the incoming ends of telephone lines to efiect the extension of these lines; special operators responsive devices permanently associated with the telephone lines; and means controlled by the regular operator for operating said responsive devices independently of the connecting ends of the line extensions under her control and by way of the incoming ends of the telephone lines.

29. A telephone exchange system including telephone lines extending to an exchange; line extensions for uniting lines in conversation; electro-magnetic switches for effecting the interchangeable association of the line extensions with the incoming ends of telephone lines to eliect the extension of these lines to a regular operators position; other line extensions pertaining to a special operators position for uniting lines in conversation and in interchangeable association with the incoming ends of telephone lines to effect the extension of these lines; special operators responsive devices permanently associated with the telephone lines; and means controlled by the regular operator for operating said responsive devices independently of the connecting ends of the line extensions under her control and by Way of the incoming endsiof the telephone lines.

30. A telephone exchange system including telephone lines extending to an exchange; line extensions for uniting lines in conversation and in interchangeable asso-' ciation with the incoming ends of telephone lines to eflect the extension of these lines to a regular operators' position; other line extensions pertaining to a special operators position for unitin lines in conversation and in interchangea le association with the incoming ends of telephone lines to efiect the extension of these lines; special operators' responsive devices individual to and permanently associated with telephone lines; and means controlled by the regular 0perator for operating said responsive devices independently of the connecting ends of the line extensions under her control and by yvay of the incoming ends of the telephone mes.

31. A telephone exchange system including telephone lines extending to an exchange; line extensions for uniting lines in conversation; electro-magnetic switches for effecting the interchangeable association of the line extensions with the incoming ends oftelephone lines to effect the extension of these lines to a regular operators position;

other line extensions pertaining to a special n, 1915. v ELMER R. CORWIN. Witnesses G. L. Cases, ETTA 'L. nrrn. 

